What is companion planting, and why would you do it?
Companion planting is the planting of different crops close together for added benefits, including pest control, pollination and to increase productivity.
After trialling many plant combinations, I find that the most important part of companion planting is proximity. Just like us, plants appreciate buddies: they don’t like being a long way from other plants, especially if they are small and more vulnerable.
For sure, there are certain combinations of plants which work better than others. However, these are less clear cut than is sometimes claimed, e.g. that the smell of onion leaves deters carrot root flies.
In fact, my first attempt at sowing carrots between onions resulted in a lot of root fly damage in the carrots!
Companionship is relevant from a plant's first day of life. Propagation works better when you have seeds and seedlings in a small area where they can be carefully looked after, i.e. a nursery.
Whether planting or sowing direct, closer spacings work better for seedlings, followed by thinning for an early harvest. This works, for example, with carrots, which can be sown in the same drill as radishes. The radish help to mark rows of germinating carrots, and you can harvest roots of radish just before the carrots start to use up all the space and light.
Multisowing is an excellent example of companionship. This includes starting 4-10 seeds all in a clump and then planting that clump without thinning. The number of seedlings per clump depends on which vegetable you are sowing: see my website for the best number of clump seeds for each vegetable.
Many gardeners on social media have told me that they are enjoying the ease and productivity of multi sowing, then planting in clumps.